One of the fruit items on your Fourth of July cookout list may be a watermelon. And there are plenty of myths on to how to choose a good one. Chad Skelton of Fat Boys Produce says he hasn't found any truth to the straw and fingernail scrapping myths. He suggests looking for a very round watermelon with a dull look. "You want to make sure when you knock on it, if it's a hollow sound, that's always better. A thud means there is more water inside of it so it's not a particularly good watermelon." Skelton also says to look at the lines on the watermelon and see if they're about a quarter of an inch thick. He also says if the watermelon is dark green, then it's a good one to choose.